It was one of the most memorable performances in the storied history of the GRAMMY Awards. On Jan. 26 GRAMMY winner John Legend took the stage on the 56th telecast and threw himself into a confident performance of his ballad, "All Of Me." Performing in a solo piano setting, both television and live audiences watched in hushed amazement as Legend sang passionately of his devotion to his wife, Chrissy Teigen.

This week, the emotional ballad has notched it second week atop the Billboard Hot 100.

For Legend, "All Of Me" is something of a victory lap. In 2004 the singer/songwriter splashed onto the global music scene with his Top 25 piano ballad, "Ordinary People." Some 10 years later, Legend's first Hot 100 chart topper appears to have touched off an unprecedented surge of Top 40 piano balladry.

In 2011 Adele's GRAMMY-winning piano ballad "Someone Like You" topped the Hot 100 and became the most downloaded digital single of all time by a female artist in the UK. The first song to win Best Pop Solo Performance honors at the 54th GRAMMY Awards, "Someone Like You" was also the first ballad featuring only voice and piano to peak at No. 1 in the history of the Hot 100. In April 2013 Bruno Mars' hit "When I Was Your Man" became the second piano-and-voice-based ballad to top the Hot 100. The song, which has been certified quadruple-platinum in the United States, was nominated for Best Pop Solo Performance for 2013.

Rihanna's GRAMMY-nominated hit "Stay" featuring Mikky Ekko has sold nearly 8 million units worldwide, and was among the best-selling global singles of 2013. Earlier in 2010, Christina Perri's hit "Jar Of Hearts" clocked 31 weeks on the Billboard Hot 100, and to date has sold more than 3 million digital copies in the United States. More recently, A Great Big World's hit "Say Something" featuring Christina Aguilera charted at No. 4, bringing the duo from obscurity to Top 40 fame.

Perhaps what's most interesting about these hits is how they buck conventional industry wisdom, which once stated that piano and voice alone weren't enough to sell a song. Of course, classic piano ballads, such as the Beatles' "Hey Jude" and "Let It Be," have traditionally commenced with piano and voice, before experiencing mid-song explosions of guitar, bass and drums. But with just piano and vocals, there are no added sonic elements to divert the listener's focus.

Legend was so inspired by the success of his drum-less new single that his current All Of Me Tour is an acoustic affair mostly showcasing him and his piano.

"The entire tour is stripped down," Legend says. "There's nothing to hide behind … but there's also nothing to distract from the voice and the lyrics of the song. I think it focuses the audience in that stripped-down state."

Asked why naked piano balladry has all of the sudden taken off, Legend opines that the phenomenon is about audiences seeking more humanity and musical austerity in contrast to the searing intensity of most popular music.

"I think we need a break from doomp, doomp, doomp," he says, emulating the automated rhythms featured in an increasing number of modern pop hits. "Sometimes you need some clarity, something that goes straight to the heart. I think [piano balladry is] more striking when you hear it."

During the recording of "All Of Me," Legend experimented with drums and bass, but ultimately found the rhythm section to be limiting.

"Sometimes, when you apply production to a song, or put a particular arrangement on it, you narrow the scope of who might listen to it," he says. "I think leaving 'All Of Me' stripped down made it more of a multiformat success, because it didn't feel bound by a certain sound, or style of production."

A Great Big World singer/songwriter Chad Vaccarino attributes the piano ballad phenomenon to audiences craving emotionalism and musical intimacy.

"Everyone wants to connect, maybe more now than ever," says Vaccarino. With a quieter song you can really connect because it's personal. The lyrics seem more upfront and profound."

Composed five years ago, "Say Something" is a deeply intimate song that chronicles the waning days of a fading relationship, so much so it almost gives listeners the feeling that they're eavesdropping. Fellow bandmate Ian Axel says the tune's nearly naked piano arrangement was integral to conveying that personal feeling of loss.

"[Chad and I] were both feeling very alone and both had our own separation experiences, which is how that song came about," says Axel. "We wrote the song because we needed to. It was our therapy, and it just poured out of us.

"I think we both knew that we wanted the song to be as stripped-down as possible, because the emotion behind it is so heavy. We didn't want that to be covered up with production."

With so many artists enjoying major success with piano ballads, it seems inevitable that the trend will continue. But the ascent of piano balladry may also signal a paradigm shift toward keyboard-dominated pop music. It seems fair to ask: Is piano balladry electro-pop's "unplugged" cousin, with both styles heralding a new age of keyboard-dominated pop?.

"If there is some kind of shift happening," Vaccarino says, "how awesome to be a part of it!"

(Bruce Britt is an award-winning journalist and essayist whose work has appeared in The Washington Post, USA Today, San Francisco Chronicle, Billboard, and other publications. He lives in Los Angeles.)

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